In recent years, replacing cathode-ray tubes conventionally used as display devices, so called flat panel displays have become the mainstream and are expanding their market. Among others, liquid crystal display devices are slim, light-weight, power-saving, and high-definition, and are used in wide areas such as in television monitors, personal computers, digital still cameras, and cellular phones.
Here, a liquid crystal display device is typically composed of a liquid crystal module formed of a liquid crystal panel, having liquid crystal sealed between a pair of opposing electrode substrates, and a polarizing plate; a backlight device that illuminates the liquid crystal module from behind; and various circuit boards that are used for driving the liquid crystal module.
FIG. 5 is an exploded perspective view of an edge-lit backlight device 1 (hereinafter referred to as the backlight device 1). The backlight device 1 has a casing 2, formed by combining together a first frame 2a and a second frame 2b, that houses thereinside a reflective sheet 5, an optical sheet 5, a light guide plate 4, a linear light source 7, and a reflector 6 that houses thereinside the linear light source 7.
Here, the optical sheet 3 has a diffusion sheet and a light-condensing sheet laid together, and is disposed on the top surface of the light guide plate 4. The reflective sheet 5 is disposed on the bottom surface of the light guide plate 4. The linear light source 7 is disposed at a position facing a side surface of the light guide plate 4. In addition, the linear light source 7 has its opposite ends held, by holding members (unillustrated), inside the reflector 6. The light guide plate 4 and the reflector 6 are held in a predetermined position by being sandwiched between the first frame 2a and the second frame 2b from above and below.
FIG. 6 is a perspective view of the backlight device 1 shown in FIG. 5. In the backlight device 1, light emitted from the linear light source 7 enters the light guide plate 4 through a side surface thereof and repeats irregular reflection to pervade the whole light guide plate 4, is then reflected upward from the reflective sheet 5 disposed on the bottom surface of the light guide plate 4 to exit the light guide plate 4 through its top surface, and then passes through the optical sheet 3, to illuminate a liquid crystal panel (unillustrated) evenly.
Here, the reflector 6 reflects the light from the linear light source 7 towards the light guide plate 4 to lead the light into the light guide plate 4. For replacement of the linear light source 7 housed inside the reflector 6, there is generally known a method of replacement which involves taking out the linear light source 7 together with the reflector 6 from the casing 2.
An insertion opening 8 is generally formed in a side wall of the casing 2 of the backlight device 1. By sliding and thereby pulling out the reflector 6 through the insertion opening 8 in the direction indicated by an arrow in the diagram, it is possible, without disassembling the backlight device 1, to take out a reflector 6 part alone. In addition, by inserting one end of the reflector 6 through the insertion opening 8 and sliding it into the space between a side surface of the light guide plate 4 and a side wall of the casing 2, it is possible to assemble the reflector 6 into the casing 2.
Here, with a view to suppressing variations in optical characteristics of the backlight device 1 and achieving compactness and slimness of the device as a whole, generally, in the space between the side surface of the light guide plate 4 and the side wall of the casing 2, only a free space for housing the reflector 6 is provided and almost no extra clearance is provided. Thus, in the course of sliding the reflector 6, friction occurs between the casing 2 and the reflector 5. This makes it difficult to take out and insert the reflector 6, lowering the efficiency of the assembling-in and replacement of the reflector.
To solve the above problem, there is conventionally proposed (Patent Document 1 listed below) a device in which a predetermined clearance is provided between a casing and a reflector and in which the reflector is held inside the casing by parts of lamp rubbers, provided at the opposite ends of the reflector, that project outward from the outer circumferential surface of the reflector.    Patent Document 1: JP-A-2001-281658 Publication